The present invention relates to a technology for knowing the division of a communication range which occurs at a time of a fault and for maintaining communication in a system that manages and controls a network including a plurality of communicating devices.
There are a transmission network and an Internet Protocol (IP) network, the transmission network including a plurality of transmitting devices that set in advance the information on data to be transferred in devices corresponding to an entry and an exit before transferring the data, the IP network including a plurality of routers (referred to also as “communicating devices”) that determine the destination of packet transfer on the basis of an IP address. Network control on the IP network dynamically selects an optimum path on the basis of the condition of the entire network in accordance with a network control packet of an IP path control protocol including Border Gateway Protocol (BGP) and a signaling protocol including Resource Reservation Protocol (RSVP), for example. However, in a case where a fault has occurred, the transmission network would select an alternative path designed in advance. On the network where the IP network and the transmission network are connected to each other, another network may be selected as an optimum path by the path selection of the IP network even though it may be better to transfer data via the transmission network depending on the condition of the fault that has occurred.
In order to make the differences in such network control systems less influential, JP-2013-026829-A discloses a system in which the IP path control protocol and the signaling protocol are analyzed with a general-purpose server. A result of the analysis is then converted into a setting for transmitting devices so that the control of a transmission network and the control of an IP network are operatively associated with each other. JP-2013-026829-A discloses a server that makes the transmission network virtually behave as one router and functions as a virtual router. This server is connected to adjacent routers by transmitting and receiving network control packets to and from the adjacent routers, converts a result of processing of the network control packets to and from the routers into a path setting for the transmission network, and sets a path connecting the routers within the transmission network. The virtual router thereby constructs a network for data transfer in the system. This system makes the setting of the transmission network operatively associated with the network control of the IP network, whereby the transmission network and the IP network are unified by the network control of the IP network. Thus a mismatch in path selection at the time of a fault is eliminated.